On the first day you shall have a holy convocation; you shall do no customary work on it.
Leviticus 23:7
Surrounding context
23:6 And on the fifteenth day of the same month is the Feast of Unleavened Bread to the LORD; seven days you must eat unleavened bread.
23:7 On the first day you shall have a holy convocation; you shall do no customary work on it.
23:8 But you shall offer an offering made by fire to the LORD for seven days. The seventh day shall be a holy convocation; you shall do no customary work on it."'